Background plateau manipulation for display device power conservation

ABSTRACT

Described herein are systems and methods that that reduce power consumption for an electronics device that includes a display. The power conservation systems and methods alter background video information not needed for interactive use when a user returns to a display after some period of inactivity. Power conservation also preserves video information for one or more graphical user interface items. Preserving a graphics item maintains a person&#39;s ability to detect the graphical user interface item, and return to it at a later time, even though the background video information has been altered to conserver power.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/658,259, filed on Oct. 23, 2012, which is a continuation of U.S.patent application Ser. No. 12/777,092, filed on May 10, 2010, which isa continuation of U.S. Pat. No. 7,714,831 issued on May 11, 2010 andclaimed priority under 35 U.S.C. §119(e) from U.S. Provisionalapplication No. 60/692,176 filed on Jun. 20, 2005, U.S. Pat. No.7,714,831 is also a continuation-in-part of U.S. Pat. No. 7,580,033issued on Aug. 25, 2009, and claimed priority under 35 U.S.C. §119(e)from U.S. Provisional application No. 60/487,761 filed on Jul. 16, 2003,the entire disclosures of each of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to systems and methods that reduce power consumedby an electronics device including a display. More particularly, thepresent invention relates to techniques for conserving power by alteringvideo information for background portions of a display area.

2. Description of the Related Art

Video output consumes a significant amount of power for a laptop ordesktop computer. Other computing systems and electronics devices—suchas handheld computing devices, cellular telephones and musicplayers—also devote a large fraction of their power budget to video.Power consumption sensitivity increases for portable devices that relyon a battery having limited energy supply.

Currently, commercially available power conservation techniques alter anentire image at once. Most techniques uniformly shut down a display orunvaryingly modify all video output in an image after some predeterminedtime. These techniques usually impede a person's ability to see graphicsitems and further use the computing device. Frequently, a personresponds by reactivating the entire display—at full power. As a result,little power is saved.

SUMMARY OF THE INVENTION

The present invention provides systems and methods that reduce powerconsumption for an electronics device that includes a display. The powerconservation systems and methods alter background video information notneeded for interactive use when a user returns to a display after someperiod of inactivity. For example, the methods may decrease theluminance for background video information outside any graphical userinterface items.

Power conservation also preserves video information for one or moregraphical user interface items. Preserving a graphics item maintains aperson's ability to detect the graphical user interface item, and returnto it at a later time, even though the background video information hasbeen altered to conserver power.

In one embodiment, the background alterations decrease luminance forbackground video information. This often makes graphics componentsincluded in a display area more detectable to a user, which facilitatesreturn to the display area—even though the majority of background videoinformation has been altered to conserve power.

In one aspect, the present invention relates to a method for reducingpower consumed by an electronics device that includes a display device.The method includes altering background video information to producealtered background video information such that the display device willconsume less power when displaying the altered background videoinformation than an amount of power that would be required to displaythe background video information without the alteration. The method alsoincludes at least partially preserving video information for a graphicaluser interface item. The method further includes displaying the alteredbackground video information with the preserved video information forthe graphical user interface item.

In another aspect, the present invention relates to a rate-based methodfor reducing power consumed by an electronics device that includes adisplay device. The method includes altering video information for agraphical user interface item at a first rate to produce altered videoinformation for the graphical user interface item. The method alsoincludes altering background video information at a second rate that isgreater than the first rate. The method further includes displaying thealtered video information for the graphical user interface item and thealtered background video information.

In yet another aspect, the present invention relates to a computerreadable medium including instructions for reducing power consumed by anelectronics device that includes a display device.

These and other features of the present invention will be presented inmore detail in the following detailed description of the invention andthe associated figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D illustrates this contrast effect of human visual processingand how the present invention may be used to enhance detection of agraphics item.

FIG. 2A illustrates video information output on a display devicesuitable for use with a laptop computer or desktop computer inaccordance with one embodiment of the present invention.

FIG. 2B illustrates the display device of FIG. 2A after videoinformation alteration and graphical user interface item preservation inaccordance with a specific embodiment of the present invention.

FIG. 3A illustrates a handheld computer device in accordance with oneembodiment of the present invention.

FIG. 3B illustrates the handheld device of FIG. 3A after videoinformation alteration and graphical user interface item preservation inaccordance with a specific embodiment of the present invention.

FIG. 4 shows video information alteration for an exemplary pixel for anLCD device to achieve power conservation in accordance with a specificembodiment of the present invention.

FIG. 5A illustrates a process flow for reducing power consumed by adisplay device in accordance with one embodiment of the invention.

FIG. 5B illustrates a process flow for reducing power consumed by adisplay device in accordance with another embodiment of the invention.

FIG. 6 illustrates an exemplary computer system suitable forimplementing the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference toa few preferred embodiments thereof as illustrated in the accompanyingdrawings. In the following description, numerous specific details areset forth in order to provide a thorough understanding of the presentinvention. It will be apparent, however, to one skilled in the art, thatthe present invention may be practiced without some or all of thesespecific details. In other instances, well known process steps and/orstructures have not been described in detail in order to notunnecessarily obscure the present invention.

The present invention alters background video information in a displayarea for a display device to permit power conservation for the displaydevice (or an electronics device that includes the display device). Forexample, the video alterations may include luminance and RGB levelreductions that require less current per pixel for an OLED displaydevice. Techniques for LCD power conservation according to the presentinvention are also described below.

In addition to saving power, the background video alterations may alsoenhance visual detection of graphics items included in a display area.In one embodiment, the alterations darken or otherwise dull thebackground video, which makes the graphics components in a display areamore visually noticeable relative to the altered background. In humanvisual processing, this is referred to as the contrast effect. As avisual analog: when a flower is placed in front of a bright background,its colors will appear duller than when it is placed in front of a darkbackground. Color and visual recognition thus improves when the floweris placed in front of a darker background.

FIGS. 1A-1D illustrate this contrast effect of human visual processingand how the present invention alters background video information toenhance detection of a graphics item 5 and/or save power. FIGS. 1A-1Dshow several video output states (2, 4, 10 and 12) of a graphics item 5and a background 6.

The vertical column in each state quantifies relative luminance betweengraphics item 5 and background 6. For example, one suitable measure forquantifying the relative luminance is average luminance, or the averageof luminance values for pixels used in displaying each of graphics item5 and background 6. The average luminance may be set in a range of 0-240or normalized for each pixel, for example. Other comparative luminancemeasures are also suitable for use to compare graphics item 5 and abackground 6.

As shown in FIG. 1A, a first state 2 corresponds to perception of item 5when a background 6 is at a zero luminance (state 2 thus shows anabsolute threshold luminance 7 for detecting graphics item 5). Humanvisual processing relies on a minimum distinction criterion between theluminance of item 5 and the surrounding—or background—luminance todetect item 5 when it is visually presented with the background. In thisinstance, a luminance difference between graphics item 5 and thebackground luminance of zero represents the minimum luminancedistinction criterion (as shown, luminance 7, which is relative to zeroin state 2, refers to the minimum luminance needed to detect graphicsitem 5). If this minimum luminance difference decreases and becomes toosmall, most people will not be able to visually discern item 5 frombackground 6.

As shown in FIG. 1B, a second state 4 corresponds to perception of item5 when item 5 includes an elevated luminance 9 and is presented with abackground 6 that has an elevated background luminance 8. In thisinstance, elevated luminance 9 maintains the minimum distinctioncriterion luminance 7 relative to background luminance 8, and graphicsitem 5 remains visible in when presented with background 6.

As the luminance difference between the two increases, item 5 typicallybecomes easier to detect and discern from background 6. This contrasteffect applies to visual processing in general, and is used by thepresent invention in the context of altering video information on acomputer display.

The luminance of background video information in a display thus affectsdetection of graphical user interface items presented with thebackground. A power conservation designer can alter background videoinformation to accomplish one or more goals.

In one embodiment, power conservation design decreases backgroundluminance to make graphics item 5 more detectable on a display device.This occurs by reducing luminance of the background video information 6relative to luminance for the graphical user interface item 5. State 10of FIG. 1C shows this graphically, where a new background aggregateluminance 11 reduces to create a large relative luminance differencebetween graphics item 5 and background 6, which eases or improvesperception of graphics item 5.

In another embodiment, decreasing the background luminance allows agraphics item 5 to be displayed at a lower luminance while stillmaintaining detectability of graphics item 5. In other words, so long asthe minimum detection criterion is not breached, the luminance ofgraphics item 5 may decrease with the reducing background luminance.State 12 in FIG. 1D shows this dual decrease; graphics item luminance 14minus background luminance 11 is greater than or equal to minimumdetection luminance 7. This option is useful to permit alteration ofgraphics item 5, e.g., to further conserve power in an OLED displaydevice. This option is also useful in LCD devices to bring all videoinformation in a display area under a new maximum luminance that permitsa lower backlight luminance level (and thus less power consumption forthe LCD, see FIG. 4) to be used.

Power conservation design may implement states 10 and 12 to varyingdegrees, e.g., to make information more or less visible, or to save moreor less power, as desired. Combinations of states 10 and 12 may beimplemented.

Graphics components made more visible by background video informationalterations may include windows, icons, toolbars, and/or portionsthereof. The background video information typically occupies a largefraction of a display area outside these smaller items. As a result,alterations to the background video information may dominate perceivedaggregate luminance for the entire screen, and thus drive energyconservation for the display device (e.g., OLED or LCD device) orelectronics device.

Power conservation methods and systems described herein alter backgroundvideo information such that the alteration decreases power consumptionfor a display device or an electronics device. The background videoinformation is altered at some time (e.g., due to inactivity in thedisplay area) according to power conservation system design. Forexample, a person may stop using a handheld or laptop computer for sometime. The present invention identifies at least one graphical userinterface item that may be relevant to a person when the person returnsto using the device. Video information for the background alters (e.g.,darkens) while the graphical user interface item is at least partiallypreserved so as to maintain a person's ability to subsequently detectthe graphics item.

A background video alteration may include decreasing the brightness andluminance, altering color for the background video information to makethe background color duller, etc. Several suitable alterations aredescribed below. Background video alteration may occur once, multipletimes, or continuously according to power conservation control. Often,alteration produces or progresses to a state where the background videoinformation is significantly visibly degraded—or even unrecognizable.For example, luminance for the background video information may bereduced to black, or some minor fraction of its original luminancelevel.

These alterations may degrade visual quality and/or perceptibility ofthe altered background video information. In one embodiment, thegraphical user interface item(s) are left untouched and unaltered. Inanother embodiment, video information for the graphical user interfaceitem is also altered to decrease power consumption. In either case, thepresent invention preserves a person's ability to see and detect thegraphical user interface item(s) at a later time when the backgroundvideo information has been significantly altered.

The amount of power conserved will depend on the display device. OLEDdevices are current driven devices where electrical current flow toindividual pixel elements varies with light output and video informationfor each pixel. Reducing RGB values for each pixel (or luminance, whichalso reduces RGB values) draws less current on a pixel-by-pixel basis.For many LCD devices, perceived luminance at each pixel of the LCD is acombination of backlight level and transmissivity of the videoinformation using pixilated filters. To reduce power, the graphicscontroller may alter video information so as to reduce transmissivity toa point where a lower backlight level may be used when displaying lowerluminance video information. Hardware power consumption (andconservation) is described in further detail below.

The present invention at least partially preserves visual perception forportions of a display area that are typically returned to afterinactivity, including graphics items such as icons, windows or windowborders, and toolbars. When a user returns to the display device aftersome period of inactivity, even though the background video informationhas been altered and degraded (and corresponding power savingsachieved), the user may still readily detect and recognize a preservedgraphics item and use it to readily return to usage of the electronicsdevice without any intermediate steps or without activating the entiredisplay, e.g., just to check the time. The present invention thuspreserves the person's ability to see and detect a graphical userinterface item and maintains their ability to quickly return to usage ofthe device. This also avoids annoyance by users who prefer to be able tosee some active video at any time, which assures a user that a computerhas not entered a hibernate mode (entire screen shut-downs are oftenconfused by users as a hibernate mode, are very noticeable in theirsudden luminance change, and commonly cause a user to re-activate anentire display to avoid entering the hibernate mode, resulting inminimal power savings).

The present invention finds use with a wide array of display devices andelectronics devices. For example, desktop and laptop computers with12-20″ display areas, measured diagonally, are now common and maybenefit from techniques described herein. The present invention isparticularly useful for portable electronics devices powered from abattery or other limited source of energy. Video power conservationtechniques described herein may significantly extend battery longevityand useable time for a portable electronics device.

FIG. 2A illustrates video information output on a display device 40suitable for use with a laptop computer or desktop computer. While thepresent invention will now be described as video information, graphicaluser interface items, graphics components and hardware components, thoseskilled in the art will recognize that the subsequent description mayalso illustrate methods and discrete actions for reducing powerconsumption for a display device and associated electronics device.

Display device 40 displays video information, and may include a liquidcrystal display (LCD) device, for example. Other display devices andtechnologies are suitable for use.

Display device 40 outputs video information for a laptop or desktopcomputer within a display area 44. Display area 44 refers to a currentimage size of a display device. Pixel dimensions may characterize thesize of display area 44. Physical dimensions (e.g., inches) that span animage produced by the display device may also characterize the size ofdisplay area 44.

An electronics device, such as a desktop, laptop or handheld computer,often runs a graphics-based user interface 42. The graphics-based userinterface 42 facilitates interaction between a user and a computerand/or between the user and one or more programs run on the computer.Several suitable graphics-based user interfaces 42 are well known andcommercially available, such as those provided by Microsoft of Redmond,Wash., and Apple Computer of Cupertino, Calif., for example.

The video information refers to data for display using the displaydevice 40 to produce a visual representation. The video information istypically stored as data in a logical manner using values assigned topixel locations. The pixel locations may correspond to a pixelarrangement used for device 40 and/or an arrangement used for storingthe data. Exemplary color schemes suitable for assigning values to videoinformation are described below. Stored video information may include aresolution that may or may not match a resolution for display device 40.For example, picture video information used for background 48 may bestored as a bitmap having a resolution that does not match theresolution of display area 44.

Referring to FIG. 2A, video information output on LCD 40 currentlyincludes graphical user interface items 41 and 43. In one embodiment, agraphical user interface item (or graphics item) refers to a graphicscomponent for display as a discrete visual object on display device 40.The graphical user interface item may include a toggle, toolbar, icon,clock, and/or other small graphics component relevant to usage of theelectronics device. For example, each graphics item may include videoinformation corresponding to a program run on interface 42 or to visualoutput for an interactive feature of interface 42. The graphical userinterface items may allow a user to select or initiate a program offeredon user interface 42, use or select a feature offered with interface 42,input data, display information, open programs, open and minimizewindows, etc. As shown in FIG. 2A, graphical user interface itemsinclude icons 41 related to programs offered by interface 42 and atoolbar 43 associated with interface 42. In general, the presentinvention is not limited to any particular graphical user interface itemprovided on a display device or function related thereto.

Icons 41 are popular graphical user interface items and typicallyinclude a characteristic graphics component that identifies andcorresponds to a particular program. Some icons 41 provide an initiationshortcut to a program, while others initiate a menu for interface 42.Popular programs include word processing programs, file navigationprograms, Internet Browsers, drawing programs, music player programs,and video games, for example. The examples shown include a trash icon 41a, an envelope icon 41 b to initiate an email program available to theelectronics device and offered by interface 42, and a dollar icon 41 cto initiate a money management program. Other icons may be used and areknown to those of skill in the art. A user may select or initiate aprogram by positioning a pointer and selecting the visual icon 41 for aprogram.

Toolbar 43 is a visual tool provided by graphics-based user interface 42that includes a number of graphics items to help a user interact withthe electronics device and programs provided thereon. Toolbar 43includes a toggle 43 a for each program currently active in display area44, a pull-down menu 43 b for accessing programs and options offered bythe graphics-based user interface 42, and a clock 43 c. Selecting atoggle 43 a displays or minimizes a graphics item corresponding to thetoggle 43 a.

Graphics items 45 and 47 are also shown in display area 44 and eachcorrespond to video output for a program currently running on userinterface 42. Rectangular windows are common graphics items and may varyin size from a maximum size that roughly spans display area 44 (minustoolbar 43) to smaller sizes within display area 44. The rectangularwindows may also be operated in minimized states where the program isactive but the graphics item is not visible. A toggle 43 a for theprogram allows switching between these states. For FIG. 2A, graphicsitem 45 includes a rectangular window that corresponds to a wordprocessing program, while item 47 includes a window that corresponds toa file navigation program.

Background 48 represents a backdrop graphics item for graphics-baseduser-interface 42, and may include a picture, single color or otherbackdrop graphics. Background 48 typically includes its own set ofbackground video information 49, which may separated for alteration andmanipulation to conserve power as described herein. In one embodiment,the background video information generally refers to video informationin a display area used for backdrop visual appearance or any videoinformation in a display area. This typically includes all videoinformation other than that included in graphics components associatedwith active programs, icons, toolbars, windows, etc., whose videoinformation is to be preserved. Often, the background video informationis not associated with a program actively being used, such as wordprocessing and file navigation windows.

FIG. 2B illustrates display area 44 as a result of inactivity inaccordance with a specific embodiment of the present invention. Thepresent invention alters background video information 49 such that adisplay device outputting the altered video information consumes lesspower than an amount of power required to display the video informationwithout alteration. As shown, luminance for the background videoinformation 49 is reduced. Additional power conservation alterationswill be described in further detail below.

As shown in FIG. 2B, toolbar 43 and any toggles included therein havenot been decreased in luminance. In addition, video information foricons 41 has not yet been altered. Graphics items 45 and 47 have beenaltered and darkened. In another embodiment, graphics items 45 and 47—ora portion of each—are preserved with icons 41 and toolbar 43. Forexample, border portions of graphics items 45 and 47 may be preserved tofacilitate subsequent edge detection of each window using the preservededge information for each window.

In another embodiment, the present invention alters video informationfor icons 41 such that border portions for each icon 41 are subsequentlyillustrated with increased contrast relative to internal portions ofeach icon. More specifically, video information in internal portions ofeach icon 41 may be altered while outer portions of each icon 41 remainunmodified. Background video information 49 that borders each icon mayalso be preserved to enhance edge detection of each icon 41 and quickvisual recognition. This allows icons 11 to be recognized based on theiredge and shape information without requiring full video output from eachicon.

Color information for toolbar 43 and icons 41 may also be preserved.Many icons include one or more characteristic colors that facilitaterecognition, such as the green in dollar bill icon 41 c. In oneembodiment, the present invention preserves the characteristic colors ofa graphical user interface item. This maintains the ability to identifythe graphical user interface item based on its color appearance. Dullingbackground 48 also facilitates this color recognition, similar to theincreased processing of colors on a black or darkened background as doneby painters to increase effect of colors used in a painting.

The graphical user interface items are typically small relative to thesize of the display area 44. In one embodiment, each graphical userinterface item occupies less than about 10 percent of a display area forthe display device. This ratio may be determined by pixel countcomparison between a graphical user interface item and display area 44,for example. The exact ratio may vary and will depend on the graphicaluser interface item, display area, electronics device type (e.g.,handheld, laptop, desktop, etc.) and a particular manufacturer. In aspecific embodiment, the graphical user interface item occupies lessthan about 5 percent of a display area for the display device.

The present invention allows a user to see and readily use graphicaluser interface items 41 and 43 within display area 44—which mayconstitute a relatively small proportion of display area 44—whilereducing video output and power consumption from the rest of the displayarea 44. In contrast, conventional display devices and powerconservation require the entire display area to be active and consumepower.

FIG. 3A illustrates a handheld computer device 20 in accordance withanother embodiment of the present invention. FIG. 3B illustrateshandheld device 20 after background video information alteration inaccordance with a specific embodiment of the present invention.

Handheld computer device 20 includes a display device 22 that displaysvideo information. Individual pixel locations within a display area 23for device 22 permit allocation and addressing of video informationdisplayed within a display area 23. For example, display device 22 mayinclude an OLED display device that offers pixel dimensions of 480×640.The OLED device 22 permits video information changes for individualpixels to affect power consumption and conservation with pixelgranularity.

Handheld device 20 runs a graphics-based user interface 24 withindisplay area 23. Interface 24 facilitates interaction between a user anddevice 20 and/or between the user and one or more programs run oncomputer device 20. To do so, interface 24 outputs video information ondisplay device 20. As shown in FIG. 3A, interface 24 currently displaysa background 28 and a set of icons 26 that each corresponds to a programavailable on device 20. The icons 26 are displayed in front ofbackground 28, which includes its own set of background videoinformation and provides a backdrop environment for graphics-based userinterface 24. Two toolbars 30 are output in display area: a top toolbar30 a that includes a pull-down toggle for interface 24 and a bottomtoolbar 30 b that includes a clock.

FIG. 3A illustrates display area 23 before alteration of backgroundvideo information in display area 23, while FIG. 3B shows display area23 after alteration of the background video information. As shown inFIG. 3B, video information in background 28 has been decreased inluminance and turned to black. Lesser alterations to the videoinformation in background 28 may be used.

Notably, the present invention conserves power without substantiallycompromising usability of electronics device 20. More specifically, thevideo information is altered such that the person may still visuallydetect icons 26 and toolbars 30 in display area 23. Thus, a user maystill perceive visual information relevant for interaction afterreturning to the display after a period of non-usage. In many instances,depending on the video information and how it is altered, darkeningbackground 28 may make icons 26 more detectable. This may also includedarkening a background that was originally white, or another relativelybright shade.

Thus, as shown in FIG. 3B, the background video information alterationssimultaneously perform two functions: a) they reduce power for the OLEDdevice, and b) the help a viewer detect and find preserved graphicscomponents in a display area after video information alterations toconserve power begin.

While FIGS. 2 and 3 illustrate two specific electronics devices, powerconservation techniques described herein are also well suited for usewith other electronics devices. Other exemplary devices include cellulartelephones, portable music players, digital cameras, and other portablecomputing and electronics devices that include a video display.

Having discussed exemplary display devices and graphics, powerconservation will now be expanded upon.

The present invention may implement a wide array of video alterations toconserve power. In general, the alteration reduces the amount of powerthat would be required to display the altered background videoinformation relative to the video information without the alteration.Alterations may vary according to the video information, time, usage ofthe electronics device, the display device and its power consumptioncharacteristics, etc.

In one embodiment, video alteration occurs based on user activity—orlack thereof. Activity may comprise a) user input for one or moreprograms—as determined by each program, b) program output to theuser—again, as determined by the program, and/or c) user input in abackground or interaction with a user interface.

Interaction that qualifies as activity is related to the programs beingrun, and may vary with power conservation system design. For example,user input and activity for a word processing program running ongraphics component 45 of FIG. 2A may include: typing within the window45, positioning a pointer within the window 45, clicking a button (e.g.,using a mouse) within the window 45, manipulating menus and scrollbarswithin the window 45, a subset of these chosen by design, etc. Userinput for a music player program running on graphics component mayinclude selecting songs to be played or manipulating volume and otheraudio output features. Video output for a music player program mayinclude temporally-varying video that changes with the music based onprogram operation—without regular user input—such as an equalizer outputor a clock that counts music time as a song plays. In one embodiment ofthe present invention, the music player program maintains an activegraphics components status as a result of the temporally varying videooutput. In another embodiment, the power conservation system is designedsuch that temporally varying video output for the music player programdoes not qualify as activity. User input for an Internet browser windowmay include positioning a pointer within the window, typing addresses,and opening links, for example. In one embodiment, activity comprisestemporally varying video output provided by a program whose video outputintentionally varies over time without continued user input, such as amovie player. Video output is also common with Internet browsers and mayor may not constitute interaction based on power conservation systemdesign. User input for background 48 includes moving a pointer withinbackground 48, selecting (‘clicking’ or ‘double clicking’) an icon 41,accessing individual items on control bar 43, etc.

Inactivity for a graphics component implies a lack of interaction in theinactive portion. As activity described above depends on a programassociated with the graphics component, so does inactivity. In oneembodiment, inactivity is defined for an individual graphics componentaccording to a lack of activity for the graphics component, which willdepend on the program associated with the graphics component. Thus,inactivity for word processing graphics component 45 includes a lack oftyping within the window boundary, a lack of positioning a pointerwithin the window boundary, a lack of manipulating menus and scrollbarswithin the window boundary, etc. Inactivity for background 48 mayinclude a lack of positioning a pointer within the background 48perimeter, a lack of initiating icons and menus, etc.

In one embodiment, the power conservation methods use a thresholdinactivity time to determine when alterations to a background begin. Thepower conservation methods may alternatively alter a backgroundimmediately with inactivity in the display area. Once the thresholdinactivity time has been reached, output power for the display devicedecreases according to one or more video manipulation techniques and thedisplay device type. A user may set the threshold inactivity time via agraphics control. A threshold inactivity time may also be set accordingto power conservation design.

In one embodiment, after the threshold inactivity time, videoalterations and power conservation may continue at set power reductionintervals. The power reduction intervals determine specific times afterthe threshold inactivity time at which further video alterations areapplied. This allows the altering video information to graduallychange—and power conservation to gradually increase—over time andaccording to power conservation design and/or user preference. A usermay set the power reduction intervals using a graphics control, forexample. Alternatively, they may be set with power conservation systemdesign. In order for a power reduction interval to be met, inactivitycontinues in the display area or window for the duration of theinterval. The threshold inactivity time and power reduction intervalsare a matter of system design and user choice and may be different timeperiods.

Once the threshold inactivity time has past, the present inventionalters background video information (and possible video information fora graphical user interface item as well) such that a display device willconsume less power than that which would be required without alteration.In addition, video information outside a graphical user interface itemmay continue to adapt as time proceeds to further reduce powerconsumption. An array of video manipulation techniques may be employedby the present invention to reduce power consumption.

Power conservation as shown in FIG. 2B reduces luminance for thebackground video information. In one embodiment, the present inventionreduces the luminance for all pixels in the background by the sameamount. In other words, the altered video information becomes darker bysubtracting a constant value from the luminance value for each pixel.This effectively shifts a luminance histogram for the altered backgroundvideo information to a darker state. Such a luminance reduction may beimplemented at a threshold inactivity time and at each power reductioninterval.

The constant value may include a function of i) a maximum luminance forthe background video information (such as a percentage), ii) a maximumluminance provided by the display device, iii) a mean, median or mode ofluminance values for the background video information, or iv) a mean,median or mode of a luminance range values provided by the displaydevice, etc. A suitable percentage of the maximum luminance for thebackground video information may range from about 1 percent to about 100percent of the maximum luminance. Thus, a 100 percent reduction turnsthe background video information black at the threshold inactivity timeand maximizes energy conservation. A 1, 2 or 5 percent luminancereduction at the threshold inactivity time and each power reductioninterval thereafter steadily decreases luminance over time. Values lessthan 1 percent may be used for subtle and/or high frequency changes.Smaller alterations may be preferable to some users who prefer a lessdramatic visual change. It is also understood that the percentagereduction at the threshold activity time and each power reductioninterval may be different levels. For example, a 5 percent luminancereduction may be implemented at the threshold inactivity time, while a 2percent, 10 percent, or escalating (0.25, 0.5, 1, 2, 4, 6, 8, 10percent, etc.) reduction may be used at each power reduction interval.

In one aspect, the present invention builds a histogram for a set ofpixels being altered and reduces power consumption for the pixels usingone or more histogram-manipulation techniques. The histogram is arepresentation showing, for each pixel value (e.g., luminance orchroma), the number of pixels in an image that have that pixel value.One embodiment alters pixel values by compressing and shifting aluminance histogram. More specifically, a luminance histogram is firstconstructed for a set of pixels to be altered. The luminance histogramis then compressed on the high and low ends, e.g., about the mean,median or mode. A shift subsequently reduces the luminance values forall pixels in the compressed set by a constant. One suitable constant isa number that gives a pixel with the lowest luminance value in the newcompressed histogram a zero luminance. The altered video informationbecomes darker since the final histogram luminance varies from zeroluminance to a new maximum luminance produced as a result of thecompression and shift.

A suitable amount of luminance compression may range from about 1percent to about 50 percent of histogram luminance range. Anothersuitable compression may range from about 5 percent to about 20 percentof histogram luminance range. Compression and shifting may occur at thethreshold inactivity time and at each power reduction interval, ifdesired. This process may repeat at subsequent power reduction intervalsuntil the video information outside the graphical user interface item isalmost black or until a predetermined cutoff is reached. Suitablecutoffs include: when the maximum luminance value outside the graphicaluser interface item reaches a predetermined minimum luminance, when thehistogram reaches a minimum width, or when the difference betweensubsequent iterations is minimal.

The present invention may implement other compression and shift schemes.In one embodiment, the luminance histogram for a set of pixels iscompressed only on one side, e.g., on the high end. If the histogramcompression occurs just on the high end, the video information becomesdarker for brighter pixels only. If the histogram compression occursonly on the low end of luminance values and then a shift is applied, thevideo information becomes darker for all pixels.

Although the present invention has primarily been discussed so far withlinear and simple reductions in luminance for pixel values, a powerconservation system designer may apply more complicated video alterationand power conservation schemes. The relationship between powerreduction, video alterations, and time may be established according tosystem design. One suitable power conservation scheme applies stepwisereductions of predetermined values at predetermined times. Another powerconservation scheme employs an exponential decrease in luminance valuesas time proceeds. In this case, luminance reduction starts slowly in aninitial time span, increases gradually in some midpoint time span, andthen increases sharply in a later time span. A linear reduction based ony=F(x2), where y is a current luminance reduction, x represents the ithalteration in a number of alterations over time, and F(x2) is somefunction that increases power conservation as inactivity time passes orincreases exponentially with a number of alterations to the videoinformation. Linear constants and other mathematical operators may beinserted into the equation to alter video alterations as desired. Logicmay also be applied in the video information manipulation to achieve adesired luminance vs. time curve.

Logic that limits further alterations to video information in subsequentpower reduction intervals may also be implemented. At some point, theentire display area may be turned off. One suitable logic applies alower limit that values of individual pixels in a background may bereduced to, such as a percentage of an initial luminance or chromalevel. For example, luminance reductions may cease for a pixel once thepixel reaches from about 5 percent to about 50 percent of its initiallevel—regardless of how it reached this point. Time may also be used.For example, all video information outside the graphical user interfaceitem may be turned off or turned black at a predetermined time. Inaddition, the entire display area, including the graphical userinterface items, may be turned off at some second predetermined shut-offtime.

In another embodiment, luminance reduction occurs gradually over time atsmaller intermittent time intervals (e.g., less than a minute) and smallluminance alterations, as opposed to larger and less frequentalterations. This technique provides a more gradual power reductionwithout sharp or noticeable changes in video content. For example,luminance in an inactive portion may decrease 1 percent every 10seconds, thereby decreasing luminance by 60 percent over ten minuteswithout a large and obvious single change.

Advantageously, the present invention permits more aggressivealterations and power conservation, if desired, to background videoinformation since the video information being altered is rarely neededby a user upon return to the device after inactivity.

In another embodiment, color in the background video information isaltered to facilitate visual detection of graphics items. Morespecifically, hue reductions in the background are applied to increasecolor recognition of the graphics items by reducing the relative amountof competing color information on the screen. The chroma alterations mayinclude reductions in saturation for example to RGB values in thebackground video information. The reductions in saturation may alsofacilitate luminance alterations to conserve power. More specifically,the alterations may reduce saturation of the background videoinformation to grey shades that facilitate less noticeable backlightluminance levels in an LCD device. In another embodiment, thealterations reduce saturation of the video information to make preservedcolors in the graphics items more visibly when a user returns to thedisplay area. In either scenario, the chroma alterations may beaggressively applied at a single given alteration since the eye is lesslikely to detect chroma alterations for a large display area or if theuser is not looking directly at the display area (peripheral vision hasminimal chromatic sensitivity).

Having discussed exemplary graphics, video information preservation, andvideo information alterations, video information representation andhardware power consumption/conservation will now be described in furtherdetail. In general, video information alterations may include anychanges to video information that decrease power consumption, and arenot limited to any particular color scheme used by the hardware or bythe software that implements power conservation.

Red, green, blue (RGB) color schemes are popular and suitable tocharacterize video information according to combinations of red, greenand blue values. Video information is often stored according to an RGBscheme, while many display devices employ an RGB color scheme for videooutput. These display devices include a red, green, and blue opticalmodulation element for each pixel, such as individual RGB light emittingdiode emitters for an OLED display device, individual RGB filters for anLCD device, or a digital micromirror element used in a projector thatsequentially and selectively reflects incident red, green and blue lightfrom a lamp and color wheel into a projection lens. In many RGB baseddevices, individual optical modulation elements receive commands forvideo output that include RGB values between 0 and 255 to produce adesired video output for a pixel. For example, one greenish color mayinitially comprise red/green/blue values of 45/251/62. According toluminance reduction techniques described above, the color may bedarkened to 3/155/16, and subsequently darkened again to 2/90/9 (thismaintains the relatively same hue for the greenish color).

In one embodiment, the present invention converts data to an HSL schemeand performs video alteration in the luminance domain. In a specificembodiment, the present invention sacrifices minor changes in colorquality when performing luminance manipulation to permit greaterluminance control and to achieve luminance targets and tailor luminancealteration changes. Depending on the size of the display device, thehuman eye generally detects changes in luminance more readily thanchanges in color; while the human eye can differentiate about 10 millioncolors, this level of differentiation is usually achieved by makingside-by-side comparisons. The human eye can only identify about 300different colors from memory. Luminance and luminance differences areoften more detectable, but vary with size of the image (luminancesensitivity typically increases with display area size).

Video information alterations may be applied in a number of colorschemes, as one of skill in the art will appreciate. An HSL color schemecharacterizes video output according to a wavelength or color (hue),degree of purity of the color—or degree of separation from gray havingthe same color (saturation), and degree of brightness for the colorranging from black to white (luminance). Cyan, magenta, yellow and black(CMYK) is another color scheme regularly used to characterize videooutput from display device according to combinations of cyan, magenta,yellow and black values. In general, power conservation techniquesdescribed herein may be implemented regardless of the color scheme usedto store the video information or employed by a graphics-based userinterface, video controller or display device. Alterations and videoconservation as described herein may also apply to black and white videooutput.

Translation between the color schemes is well known to one of skill inthe art. Thus, power conservation techniques described herein may beprogrammed or stored according to one color scheme, and output accordingto another color scheme for the display device. For example, video datamanipulation techniques described herein may be implemented and storedin an HSL scheme, and then converted to and output by an RGB baseddisplay device.

Hardware power consumption and conservation will vary with displaytechnology for the display device.

OLED display devices provide pixel granularity power consumption—andpermit pixel granularity power conservation. OLED devices include a red,green, and blue individual light emitting diode or filter for eachpixel. OLED element power consumption is proportional to the lightoutput; the amount of current sent to each light emitting diode orfilter increases with each RGB color level between 0 and 255 (or othergradation). Decreasing the RGB levels then reduces the amount of powerfor each diode and pixel. For example, altering white background videoinformation RGB values of 255/255/255 to a white shade of 235/235/235reduces the amount of current sent to each individual light emittingdiode for each pixel that emits the white shade. The amount of powerconserved over the display area for the OLED display device can then bedetermined by summing the power saved for all pixels in the display areathat have been altered.

LCD display device power consumption (and conservation) largely relatesto backlight levels and their varying power consumption. LCD devicesprovide two degrees of freedom for controlling luminance perceived by auser: 1) different luminance levels provided a backlight and 2)graduated filtering by optical modulation elements for each pixel. FIG.4 shows video information alteration for an exemplary pixel for an LCDdevice to achieve power conservation in accordance with a specificembodiment of the present invention. Four luminance states 100 a-d areshown at three different times: t=0, t=1 and t=2.

Scale 102 illustrates a number of backlight luminance levels 103 offeredby a backlight used in an LCD device. In this simple illustration, theLCD provides ten discrete backlight levels 103, numbered from 0 to 10,where 0 is off and 10 represents the maximum luminance for thebacklight. Each increasing integer luminance level between 0 and 10provides a proportionate increasing luminance (each level representsabout 10% the maximum luminance) for the backlight. Each level alsoconsumes more power. More complicated backlight levels are contemplatedand suitable for use.

Transmissivity refers to the amount of light passage provided by opticalmodulation elements for a pixel. Many LCD devices include red green andblue (RGB) filters that act as optical modulation elements, where eachfilter regulates passage of white light produced by the backlightthrough a colored filter element to produce red, green and blue light,respectively. Transmissivity for each pixel may then be expressed usingRGB values sent on control signals to each RGB filter. LCD devicescommonly include modulation elements that respond to RGB transmissivityvalues ranging from 0 to 255 (or normalized from 0 to 1). The videoinformation and transmissivity may also be expressed and converted fromanother video data scheme, such as HSL luminance. For example, luminancefor each pixel may be provided at integers between 0 and 240, where zerorepresents black (full filtering and blocking of light provided by thebacklight for each RGB filter) and 240 represents white (no filteringand blocking of light provided by the backlight).

As the term is used herein, ‘aggregate luminance’ refers to a luminanceoutput to (or perceived by) a viewer of an LCD device. This aggregateluminance combines luminance effects provided by a) the backlight and b)filtering provided by the optical modulation elements for each pixel.The aggregate luminance is typically limited to a maximum determined bythe backlight level since the pixelated filters only reduce lightcurrently offered by the backlight. For FIG. 4, maximum luminance forthe LCD device corresponds to a backlight level of 10 and luminancetransmissivity of 240. At backlight luminance level 9, the maximumaggregate luminance for video data corresponds to a luminancetransmissivity of 240 (t=2). Aggregate luminance for the pixel isdesignated as 104 a-d for FIG. 4 at each time instance.

Both the backlight level and the luminance transmissivity arecontrollable. In one embodiment, LCD power conservation leverages thetwo degrees of freedom in luminance control (and user perception) toreduce power for the LCD device.

At time t=0, the illustrated high luminance pixel (a white pixel)includes a backlight level of 10 and luminance transmissivity of 240,which corresponds to a maximum for the aggregate luminance and isdesignated as 104 a.

LCD power conservation first alters video information for the pixel.This reduces transmissivity and perceived luminance for the pixel. Forthe example at time t=1, the backlight level remains at level 10 but thevideo information is altered to reduce the luminance transmissivity to228. This provides an aggregate luminance of 104 b (a darker shade). Inthis case, information has been altered but without a backlight change,and no power conservation has yet been achieved.

At time t=2, the backlight level still remains at level 10 but the videoinformation is further altered to reduce the luminance transmissivity to224 (an even darker shade). This provides an aggregate luminance of 104c. Aggregate luminance of 104 c is noteworthy because it approximatelycorresponds to the aggregate luminance of 104 d provided by the LCDdevice for the pixel when the backlight level drops to level 9 and theluminance transmissivity returns to 240 (its original level). At thisluminance, the backlight level may drop from level 10 to level 9 whilethe luminance transmissivity simultaneously increases from 224 to240—without changing the aggregate luminance of 104 output to theviewer—or as perceived by a viewer. In this manner, it is possible toalter video data using pixel video information and transmissivity toconserve power with a person not noticing a backlight change. Powerconsumption for the backlight and LCD device reduces when the backlightlevel changes from level 10 to level 9.

For an LCD, aggregate luminance is then manipulated for all pixelsaffected by a backlight (some LCD devices include more than one) at thechange. Video information for the image is altered to produce a newmaximum luminance that is less than the next or largest availableluminance at the next backlight level. When this new maximum luminancehas been achieved, the LCD switches to the next backlight level andsimultaneously alters transmissivity to minimize impact of the backlightchange. In a specific embodiment, the transmissivity changes aredesigned to enable backlight changes without a user noticing.

Although the above example has been simplified to illustrate two degreeof freedom luminance control and power conservation using and LCD, powerconservation as described herein is not limited to such simpleexpressions of backlit luminance levels and pixel transmissivity. Theabove example employed ten backlight luminance levels; other numbers ofbacklight luminance levels are contemplated. In general, the LCD devicemay include any number of backlight luminance levels. As the granularityof backlit luminance levels increases, so does power conservation andthe ability to more readily use a lower backlight level. The backlightluminance levels also need not correspond to simple fractions of themaximum luminance or integer levels as described above. In addition,luminance transmissivity is not limited to expression using a range of1-240. Other luminance transmissivity and color schemes, such asnormalized scales, are also suitable for use. As one of skill in the artwill appreciate, the number and characterization of backlight luminancelevels will depend on the LCD used, while the number andcharacterization of video information will depend on the video schemeused to represent the video data.

Aggregate luminance thus allows a designer to relate backlight luminancelevels and pixel transmissivity for an LCD device, which permits adesigner to alter background and other video information and direct thealterations towards backlight luminance reductions. An aggregateluminance model may be built for a device that estimates luminanceperceived by a user as a combination of backlight and pixilatedtransmissivity. For example, the aggregate luminance may be used toprovide a ratio (or another suitable mathematical relationship) betweenthe backlight luminance levels and pixel transmissivity.

One video alteration embodiment for LCD use sets a high luminance limitfor a histogram of luminance after an alteration. The high luminancelimit refers to a reference luminance level for video information in thedisplay area that may be used to guide alteration, e.g., before changinga next backlight luminance on an LCD device. Video information forpreserved graphics items may rest near the high luminance limit, whilethe background video information is altered to a lesser luminance in thehistogram. This maintains visible salience of the graphics item videoinformation relative to the background video information, and allowsstepwise decreases in backlight luminance. This also allows luminancefor any pixel in the image to remain relatively constant at the momentof each backlight level change (to produce little perceptible change).And, as mentioned above, the luminance may be altered gradually overtime such that each of the transmissivity luminance changes is notindividually detectable. Further description of LCD based powerconservation suitable for use with the present invention is described incommonly owned pending U.S. Pat. No. 7,663,597 and entitled “LCD PlateauPower Conservation”, which is incorporated herein in its entirety forall purposes.

FIG. 5A illustrates a process flow 200 for reducing power consumed by anelectronics device and/or display device in accordance with oneembodiment of the invention. While the present invention will now bedescribed as a method and separable actions for reducing powerconsumption, those skilled in the art will recognize that the subsequentdescription may also illustrate hardware and/or software systems anditems capable of performing the method and actions.

Process flow 200 begins by altering background video information toproduce altered background video information (202). The videoinformation is altered such that the display device will consume lesspower when displaying the altered background video information than anamount of power that would be required to display the background videoinformation without the alteration. The amount of power saved will varywith the display device, as one of skill in the art will appreciate. Foran OLED device, the power conservation is proportional to the reductionin RGB values for each pixel, summed for the entire background. For anLCD device, one suitable conservation technique to conserve power wasdescribed above. Other techniques are suitable for use.

The background video information may be variably identified. In oneembodiment, the background video information refers to any videoinformation in a backdrop, over which all icons and other active videoinformation is overlaid. Such a backdrop may include a single color, apattern, JPEG or bitmap image, etc. In another embodiment, thebackground video information refers to any video information notincluded in selected graphics items (204) and any other active programsbeing displayed.

Process flow 200 at least partially preserves video information for agraphical user interface item (204). This implies prior selection of atleast one graphical user interface item. Selection may vary. In oneembodiment, a power conservation program run on the electronics deviceautomatically selects the graphical user interface item(s). In anotherembodiment, a user toggles a class of graphical user interface itemsusing a power conservation graphics control offered by a graphical userinterface. Some classes include: icons, toolbars, shortcut icons, andactive window or program representations, for example. This allows theuser or power conservation system designer to control what items arepreserved.

In one embodiment, the present invention preserves video informationthat facilitates visual recognition of each graphics item. This mayinclude: preserving characteristic color video information for agraphical user interface item that helps identify the graphics componentbased on its color (e.g., preserve the green in a dollar bill icon orthe blue border in a blue bordered window); preserving characteristicedge detection video information that contributes to edge and/or shaperecognition of the graphics component (e.g., the shape of a letter foran icon shaped as a letter); preserving characteristic window video thatfacilitates identification of a window (e.g., preserve window edge orcolor information for a window); and/or preserving other videoinformation that facilitates visual detection of an icon. Preserving thecharacteristic video information maintains a person's ability to locatethe graphics component at a later time, even though other portions ofthe display area have been altered to conserver power. This improves aperson's ability to visually locate a graphics component in a displayarea. Since the video information being preserved often occupies a minorpercentage of the display area, avoiding or minimizing powerconservation video alterations for these relatively small portions doesnot contribute largely to power consumption—but maintains a person'sability to subsequently locate and return to using a graphics componentand display area.

“At least partially preserves” implies that the graphical user interfaceitem remains detectable after the alterations to the background videoinformation. In one embodiment, video information for the graphical userinterface item(s) is left untouched and unaltered. Backgroundalterations may then make the graphics items more detectable (see FIG.1C). In another embodiment, video information for the graphics item(s)is also altered to decrease power consumption, e.g., for direct powerconservation in an OLED device, or to enable lower backlight levels inan LCD device. As mentioned with respect to FIGS. 1A-1D, videoinformation for one or more graphics items may be altered and degradedto various degrees—so long as a minimum detection criterion remainsrelative to the background video information. In this case, videoinformation for the graphical user interface item is typically alteredless aggressively than the video information outside its boundaries tomaintain detectability. Regardless of alteration, the present inventionpreserves a person's ability to see and detect the graphical userinterface item(s) at a later time when the background video informationhas been significantly altered.

In a specific embodiment, background video information altersimmediately upon inactivity in the display area. One suitable luminancereduction scheme decreases luminance incrementally and alters videoinformation at power reduction intervals that begin immediately uponuser inactivity and have a frequency of greater than 1 alteration every5 seconds. In this case, the incremental reductions decrease luminanceby a small amount each time such that each individual alteration is notreadily noticeable to a user. Cumulatively, however, the incrementalalterations accumulate to produce a significant change, such as a 50percent reduction in luminance for the background and graphicscomponents over five minutes, for example. The gradual rate ofalteration may be established according to power conservation systemdesign or user preference, and advantageously allows video informationto alter without substantially noticeable momentous changes (humanvisual perception is generally very sensitive to luminance changes, butdepends on the size of the display). A magnitude for each incrementalalteration may be determined by dividing a desired total alteration overa period of time by the number of intervals in the time period. Forexample, the progressive changes may occur as often as desired toproduce a backlight luminance level change in an LCD device every 30seconds. The backlight luminance level change may then occur without anyindividual changing aggregate luminance from the display being perceivedby a user.

The altered background video information and at least one graphical userinterface item are then displayed together on the display device (206).Since the background video information often occupies a major percentageof the display area, alteration of the video for these portions can leadto significant luminance decreases and power conservation—whilemaintaining a person's ability to subsequently detect and use thepreserved graphics items.

Altered video information may return—or reactivate—to its original statefrom an altered state after user activity with the display area, or asotherwise designated by a power conservation program designer.Reactivation typically displays the display area as it was initiallydisplayed before any alterations. In a specific embodiment, positioninga pointer onto an area of a display area triggers reactivation.Reactivation may also include initiating graphics window via itscorresponding toggle on a toolbar. Power conservation system designersmay also customize reactivation rules. For example, reactivation may bedesigned such that solely positioning and moving a pointer within awindow or background does not satisfy reactivation criteria. In thiscase, clicking a button on a mouse while the pointer is within thewindow, or another explicit action within the graphics component, maysatisfy reactivation.

FIG. 5B illustrates a process flow 210 for reducing power consumed by anelectronics device and/or display device in accordance with anotherembodiment of the invention. Process flow 210 begins by setting a powerconservation scheme (211). A power scheme refers to a collection ofpower options that dictate how and when video information is altered toreduce power consumption. In one embodiment, a power conservation systemis stored on a computer and implements a power conservation schemewithout user input. In another embodiment, a graphics control allows auser to set a power scheme or one or more power options corresponding totechniques described herein, e.g., select one or more types of graphicaluser interface item for video preservation.

For process flow 210, the power conservation scheme uses a thresholdinactivity time to determine when alterations to video data begin. Thethreshold inactivity time may beset by a user via a graphics control, orautomatically with power conservation system design. Once the thresholdinactivity time has been reached, video information is altered to reducepower consumption.

After the power conservation scheme has been established, process flow200 monitors user activity within the display area (213). Process flow210 continues to monitor activity over time and reacts according to anyuser activity or lack thereof (216). If user activity occurs in thedisplay area, process flow 210 then resets the inactivity monitor clockand returns to 213. If user inactivity continues until the thresholdinactivity time, then process flow 210 alters background videoinformation.

In this embodiment, video information for the graphical user interfaceitems is also altered. In this case, alterations to video informationfor the graphical user interface items occur at a lesser rate than thatfor the background video information. Process flow 200 proceeds byaltering the video information for each graphical user interface item ata first rate (220). The change may include reducing the luminance foreach graphical user interface item such that a next luminance level inan LCD device may be employed.

Power conservation also alters the background video information (222).Suitable techniques for altering video information outside the graphicaluser interface item were described above.

In this case, the video information for the graphical user interfaceitem alters at a lesser rate than the background video information. Inone temporally varying embodiment, alterations to video informationoccur at set power reduction intervals. The power reduction intervalsdetermine specific regular times at which minor but additive videoalterations are applied. In this case, alterations to the graphical userinterface item may occur less frequently (at larger intervals) than forvideo information outside the graphical user interface item. Forexample, progressive and stepwise changes to RGB values of the graphicaluser interface item may occur every twenty seconds while progressive andstepwise changes to RGB values of background video information may occurevery ten seconds. Other intervals may be used. In one embodiment, apower reduction interval from one second to about 3 minutes is suitable.In another embodiment, a power reduction interval from about 1 second toabout 10 seconds is suitable. It is understood that power reductionintervals are a matter of system design and user choice and may beinclude different time periods that those specifically provided herein.

The difference in rate of alteration may also include changes at thesame frequency—but by different amounts at each interval. In this case,the background video information is altered more aggressively at eachinterval than that of each graphical user interface item.

In one embodiment, power conservation as described herein is implementedwithout user input. In another embodiment, a computer system provides auser the ability to turn on/off power conservation or tailor the powerconservation to personal preferences that include the ability topreserve video information for one or more graphical user interfaceitems.

Inactivity within the display area may be further monitored and timed.The graphics-based user interface may include a global power saving toolthat initiates after a predetermined time of inactivity throughout theentire display area. In this case, the global power saving tool turnsoff video display for the entire display area, including the graphicaluser interface items being preserved, when inactivity reaches the globalpower saving tool time limit, e.g., such as 5 minutes.

The present invention may also relate to systems for reducing powerconsumed by a display device. The power conservation system may compriseany combination of software and hardware for carrying out actionsdescribed herein. In a specific embodiment, general-purpose computerprocessing units, instead of dedicated hardware, implement themonitoring and video alteration techniques. Further description of powerconservation systems suitable for use with the present invention isprovided in commonly owned U.S. Pat. No. 7,580,033, which wasincorporated by reference above.

The present invention finds use with computer systems such as desktopand laptop computers, personal digital assistants (PDAs), cellulartelephones, digital cameras, portable computer systems, and the like.FIG. 6 schematically illustrates an exemplary general-purpose computersystem 300 suitable for implementing the present invention.

Computer system 300 comprises a processor, or CPU, 302, one or morememories 314 and 316, input/output (I/O) circuitry 306, display device308, input device 310, and system bus 312. System bus 312 permitsdigital communication between the various components within system 300.

System 300 memory includes read only memory (ROM) 314 and random accessmemory (RAM) 316. Other memories may be included. ROM 314 stores a basicinput/output system 318 (BIOS), containing basic routines that help totransfer information between elements within computer system 300, suchas during start-up. Computer system 300 may also include a hard diskdrive and an optical disk drive, for example. The optical disk drivereads from and may write to a CD-ROM disk or other optical media. Thedrives and their associated computer-readable media provide non-volatilestorage for system 300. A number of program modules may be stored in thedrives, ROM 314, and/or RAM 316, including an operating system, one ormore application programs, other program modules, and program data.Although data storage above refers to a hard disk and optical disk,those skilled in the art will appreciate that other types of storage aresuitable for use with a computer system, such as magnetic cassettes,flash memory cards, USB memory sticks, and the like. In addition, notall computer systems, such as PDAs and other portable devices mayinclude multiple external memory options.

Processor 302 is a commercially available microprocessor such as one ofthe Intel or Motorola family of chips, or another suitable commerciallyavailable processor. Processor 302 digitally communicates with ROM 314via system bus 312, which may comprise a data bus, control bus, andaddress bus for communication between processor 302 and memory 314. CPU302 is also coupled to the I/O circuitry 306 by system bus 312 to permitdata transfers with peripheral devices.

I/O circuitry 306 provides an interface between CPU 302 and suchperipheral devices as display device 308, input device 310, audio output334 and/or any other I/O device. For example, a mouse used as inputdevice 310 may digitally communicate with processor 302 through a serialport 306 that is coupled to system bus 312. Other interfaces, such as agame port, a universal serial bus (USB) or fire wire, may also providedigital communication between a peripheral device and processor 302. I/Ocircuitry 306 may also include latches, registers and direct memoryaccess (DMA) controllers employed for interface with peripheral andother devices. Audio output 334 may comprise one or more speakersemployed by a headphone or speaker system.

Display device 308 outputs video information—both unaltered andaltered—including graphics components, backgrounds, graphics-based userinterfaces, and other visual representations of data. For example,display device 308 may comprise a cathode ray tube (CRT), liquid crystaldisplay (LCD), organic light emitting diode (OLED), or plasma display,of the types commercially available from a variety of manufacturers.Display device 308 may also comprise one or more optical modulationdevices, or the like, used in projecting an image. Projection displaydevices that project an image onto a receiving surface are becoming morepopular, less expensive, more compact; and may employ one or moreoptical modulation technologies as well as a wide variety of individualdesigns. Common optical modulation devices include those employingliquid crystal display (LCD) technology and digital mirror device (DMD)technology. When used as a display device for a computer, theseprojection devices provide the potential for a much larger image sizeand user interface.

In general, the present invention is not limited to use with anyparticular display device. The present invention is independent of anyparticular display device technology, any mechanism of light generationfor a display device, or any power consumption scheme for a displaydevice, and only assumes that power consumption for display device 158may vary with video information or visual reception of the videoinformation. In a specific embodiment, display device 158 can vary powerconsumption spatially on a pixel-by-pixel basis.

Display device 308 may also digitally communicate with system bus 306via a separate video interface, such as a video adapter 346. Videoadapter 346 assists processor 302 with video graphics processingincluding power conservation alterations described herein. Video adapter346 may be a separate graphics card or graphics processor available froma variety of vendors that are well known in the art.

Input device 310 allows a user to enter commands and information intothe computer system 300, and may comprise a keyboard, a mouse, aposition-sensing pad on a laptop computer, a stylus working incooperation with a position-sensing display on a PDA, or the like. Otherinput devices may include a remote control (for a projector),microphone, joystick, game pad, scanner, or the like. As used herein,input device refers to any mechanism or device for entering data and/orpointing to a particular location on an image of a computer display.Input as described herein may also come through intermediary devices.For example, a remote control may communicate directly with processor302, or through an intermediary processor included in another devicesuch as a hybrid entertainment device such as a set-top box orprojector. The user may then input information to computer system 300using an infrared remote control device that communicates first with theintermediary device, and then to processor 302.

In one embodiment, a graphics-based user interface implemented bycomputer system 300 displays a graphics control such as controldescribed above. To display a power conservation graphics control,processor 302 issues an appropriate command, followed by anidentification of data that is to be used to construct the graphicscontrol. Such data may include a number of power conservation controltools that allow a user to change how video data is altered. ROM 314also stores a number power conservation commands and instructions forimplementing the techniques described herein. In one embodiment, thepresent invention is practiced in the context of an application programthat runs on an operating system implemented by computer system 300 orin combination with other program modules on computer system 300.

The present invention may be implemented on a range of computer systems.In addition to personal computers such as desktop computers and laptopcomputers, a variety of other computer systems and computer devicesemploying a digital processor, memory and a display device may implementthe present invention. Handheld computers and other small portabledigital devices such as cell phones and digital cameras are increasinglyintegrating video display and computer functionality. One current trendis hybrid entertainment devices that integrate the functionality ofcomputer systems, audio devices, and televisions. Any of these devicesmay employ and benefit from the power conservation methods and systemsdescribed herein. The scope of digital computer systems is expandinghurriedly and creating new devices that may employ the presentinvention. In general, any digital device employing an output displaydevice that varies output power with video content may benefit from thepresent invention. Moreover, those skilled in the art will appreciatethat the invention may be practiced with other computer systemconfigurations, multiple display device systems, multi-processorsystems, microprocessor-based or programmable consumer electronics,minicomputers, mainframe computers, and the like.

The present invention is particularly useful to portable computingdevices run with battery power. Most handheld devices are designed torely on battery power. In addition, although the present invention hasbeen discussed with respect to reduced power consumption, energy andpower are relatively interchangeable in a discussion of the benefits ofconservation.

Embodiments of the present invention further relate to computer readablemedia that include program instructions for performing powerconservation techniques described herein. The media and programinstructions may be those specially designed and constructed for thepurposes of the present invention, or any kind well known and availableto those having skill in the computer software arts. Examples ofcomputer-readable media include, but are not limited to, magnetic mediasuch as hard disks, semiconductor memory, optical media such as CD-ROMdisks; magneto-optical media such as optical disks; and hardware devicesthat are specially configured to store program instructions, such asread-only memory devices (ROM), flash memory devices, EEPROMs, EPROMs,etc. and random access memory (RAM). Examples of program instructionsinclude both machine code, such as produced by a compiler, and filescontaining higher-level code that may be executed by the computer usingan interpreter.

Graphics controls and graphics-based user interfaces such as thosedescribed herein may be implemented using a number of computer languagesand in a number of programming environments. One suitable language isJava, available from Sun Microsystems of Sunnyvale, Calif. Anothersuitable programming environment is the Microsoft Windows® programmingenvironment, which provides a series of operating systems suitable forimplementing the present invention both on laptop computers and handheldcomputers.

Although the foregoing invention has been described in some detail forpurposes of clarity of understanding, those skilled in the art willrecognize that various modifications may be made within the scope of theappended claims. In addition, although power consumption andconservation has not been detailed for every type of display device, thepresent invention is suitable with any display technology that can varypower output with video information. Projectors, for example, consumepower based on the amount of light produced, which may be reduced usingtechniques described herein. The invention is, therefore, not limited tothe specific features and embodiments described herein and claimed inany of its forms or modifications within the scope of the appendedclaims.

What is claimed is:
 1. An apparatus comprising: a display including atleast a first portion to display first visual information and a secondportion to display second visual information; and at least one processoroperatively coupled with the display, the at least one processorconfigured to: detect an event in relation with the second visualinformation; and change the second visual information to third visualinformation in response to the event, wherein a power consumptionrequired in relation with the third visual information is less than apower consumption required in relation with the second visualinformation.
 2. The apparatus of claim 1, wherein the at least oneprocessor is further configured to reduce a current being supplied tothe second portion, as at least part of the changing.
 3. The apparatusof claim 2, wherein the at least one processor is further configured togradually reduce the current while the event is continuously detected.4. The apparatus of claim 1, wherein the at least one processor isfurther configured to maintain the first visual information bysustaining a current being supplied to the first portion while changingthe second visual information to the third visual information.
 5. Theapparatus of claim 1, wherein the event includes at least one ofsustainment of the second visual information or lack of a user input onor adjacent to the second portion for a specific time duration.
 6. Theapparatus of claim 1, wherein the at least one processor is furtherconfigured to maintain the second visual information while the event isnot detected in relation with the second portion.
 7. The apparatus ofclaim 1, wherein the at least one processor is further configured todecrease luminance level or RGB level of the second visual information,as at least part of the changing.
 8. The apparatus of claim 1, whereinthe at least one processor is further configured to display the firstvisual information via the first portion and the third visualinformation via the second portion, and wherein contrast between thefirst visual information and the third visual information is higher thancontrast between the first visual information and the second visualinformation.
 9. The apparatus of claim 1, wherein the at least oneprocessor is further configured to change the first visual informationto fourth visual information, in response to the event.
 10. Theapparatus of claim 9, wherein luminance difference between the firstvisual information and the fourth visual information is less thanluminance difference between the second visual information and the thirdvisual information.
 11. The apparatus of claim 1, wherein the at leastone processor is further configured to store the second visualinformation before the changing.
 12. The apparatus of claim 1, whereinthe display includes at least one of an OLED display or a quantum dotdisplay.
 13. An apparatus comprising: a display including at least afirst pixel to display first visual information, and second pixel todisplay second visual information; and at least one processoroperatively coupled with the display, the at least one processorconfigured to: detect an event in relation with the second visualinformation, and reduce a current of the second pixel, in response tothe event, so that the second visual information is changed to thirdvisual information.
 14. The apparatus of claim 13, wherein a powerconsumption required in relation with the third visual information isless than a power consumption required in relation with the secondvisual information.
 15. The apparatus of claim 13, wherein the at leastone processor is further configured to decrease the current when aspecific time has elapsed after the event is detected.
 16. The apparatusof claim 13, wherein the at least one processor is further configured tomaintain another current drawn into the first pixel while reducing thecurrent.
 17. The apparatus of claim 13, wherein at least one of thefirst pixel or the second pixel is at least partially composed of adiode.
 18. A method comprising: displaying first visual information viaa first portion in a display and second visual information via a secondportion in the display; detecting an event in relation with the secondvisual information; and changing the second visual information to thirdvisual information, in response to the event, so that a powerconsumption required in relation with the third visual informationbecomes less than a power consumption required in relation with thesecond visual information.
 19. A method of claim 18, wherein thechanging comprises reducing a current being supplied to the secondportion.
 20. A method of claim 18, wherein the changing comprisesmaintaining a current being supplied to the first portion.